Do I need a neutral white wire to install a 220v GFCI breaker in the main panel ?
Currently have 220v, 2 pole red hot, black hot and green ground in the circuit running pool pump timer and pump.
Or can I use the green wire as neutral? I believe the answer is no.
Please advise. Thank you.
No, you do not need a neutral "load" wire if you're running only 240V load. The GFCI will detect any imbalance between the two phases and trip if one occurs. See picture below.
The green wire can never be used for anything but a ground.
This is straightforward.
For a 240V GFCI device, it will have a neutral pigtail. That must be hooked up, for the purpose of powering the GFCI device itself.
However once that's hooked up, you are welcome to attach a 240V circuit hot-hot only.
Remember white wires used as hot need to marked with tape to indicate they are hots. Otherwise someone might put them on the GFCI neutral!
